حَرَمَ is the past form of the word يحرم = forbid/ don't give. So u can translate this sentence as (I'll forbid u from the pocket money for a whole week)

It means I'm not giving you any pocket money for a whole week ! another form of grounding and underaged person

the verb: حرم means to prevent someone from having something; deprive(of) the verb: حرّم means to make something illegal, illicit, disapproved or unacceptable usually because of a law, custom or most commonly a breach of the rules of a religion( Islam).

to forbid or to prohibit or to ban something

forbade حرم - منع forbid prohibit interdict proscribe deprive divest